Information reproducing apparatus

ABSTRACT

The disclosed information reproducing apparatus includes a transporting portion for moving a tape-shaped recording medium at one of at least two different speeds, a reproducing head for reproducing the information on the recording medium as it is moved by the transporting portion, and a detecting portion for detecting whether or not the speed of movement of the recording medium during reproduction is coincident with that of the recording medium during recording of the information.

BACKGROUND OF THE INVENTION

1. Field of the Invention:

This invention relates to apparatus for reproducing information from atape-shaped recording medium which was run at two or more differentspeeds during recording. Such reproducing apparatus includes magneticrecording and reproducing apparatus, optical reproducing apparatus andmany more various types of apparatus. However, the disclosed embodimentsare directed chiefly to an apparatus for reproducing video informationsfrom a magnetic tape on which television signals have been recorded, ora video tape recorder (hereinafter referred to as "VTR").

2. Description of the Prior Art:

Recently, high density magnetic recording has become possible, and VTRscapable of making long-time recordings and reproducing such recordingshave been developed and commercially manufactured.

For adaption to the convention format too, these are made to operate atvarious selected time modes, for example, standard and long, duringrecording and reproduction in a single VTR item. To reproduce thepicture recorded on the magnetic tape by such a dual time mode operatingVTR, it is necessary to set up the same time mode as the recordingoperation. Otherwise, because of the tape format being different, adisturbed picture would be reproduced. Manually choosing the requiredreproduction time mode while observing the reproduced images is veryinconvenient to the user. On this account, according to the prior art,when recording, the tape is given one control signal (hereinafterreferred to as "CTL" signal) for every one frame at the vicinitythereof. Then when reproducing, the number of revolutions of the capstanmotor proportional to the distance the magnetic tape has run is sensedwith a pulse generator, and how many pulses have been produced in thetime interval of occurrence of the CTL signal is counted to examinewhether or not the time mode is different between the recording and thereproduction. Upon detection of the difference, the preliminary settingof the time mode is automatically changed.

Such prior art is described by way of example with reference to FIG. 1.A magnetic tape 1 is moved in a direction indicated by arrow by acapstan 2 and a pinch roller 3. Reproduced from the magnetic tape 1 isthe video signal which has been recorded on the incline track to thelength of the magnetic tape 1 by a rotating magnetic head (not shown)fixedly carried on a rotary drum as is well known in the art. Thecapstan 2 is driven by a motor 4 through an endless belt 5 to rotate ata prescribed speed. To sense the speed of rotation of the capstan motor4, a frequency generator 6 whose output pulses are proportional innumber to the speed of movement of the magnetic tape 1 are applied to acounter 8 at a clock input terminal CK thereof. A control head 9 picksup the CTL signals of repetition in frame unit, and its output isapplied through an amplifier 10 and a waveform shaper 11 to the "reset"terminal R of the aforesaid counter 8. With such input stage, thecounter 8 recycles counting of the number of pulses in a time intervalfrom one to the next CTL signal and its outputs Q1 to Q4 are applied toa magnitude comparator 13 where they are compared with outputs of areference control 12 in which a number is preset. When this referencenumber is exceeded, the output Q5 of comparator 13 assumes a high level.That is to say, for the standard mode, the number of pulses counter 8has counted in between the successive two CTL signals is assumed to be44. Then if the recording has been operated in the long time mode, wherethe tape speed is halved, the CTL time interval becomes 1/2 times thatof the standard mode. Therefore, when the magnetic tape which has beenrun at the long time mode during recording is run at the standard modeduring reproduction, the number of pulses counted in every one CTLinterval is not 44 as normal, but only a half of that, or 22. With thereference control 12 having preset therein an intermediate numberbetween 22 and 44, therefore, that no more than the reference number iscounted during reproduction at the standard mode, shows that therecording has been operated in the long time mode. Conversely that morethan the reference number is counted, shows that the recording wasoperated in the standard mode.

However, if some of the CTL signals have failed to be recorded, as ifformats do not have what is called the control signals are employed, aproblem arises because such automatic mode setting does not result.

SUMMARY OF THE INVENTION

With the foregoing in mind, it is an object of the present invention toprovide a reproducing apparatus capable of detecting the differencebetween the running speed of a recording medium during reproduction andthe speed during recording even when no CTL signals were recorded.

More specifically, an object of the invention is to provide areproducing apparatus having detecting means for detecting whether ornot the running speed of a recording medium during reproduction iscoincident with the running speed of the recording medium duringrecording by the reproduction output of reproducing means forreproducing information signals.

Another object of the invention is to provide a reproducing apparatushaving control means upon detection of the difference between therunning speed during reproduction and the speed during recording toautomatically bring the running speed during reproduction intocoincidence with the running speed during recording.

Still another object of the invention is to provide a reproducingapparatus which, when information is reproduced from a tape-shapedrecording medium on which pilot signals such as those disclosed in U.S.Pat. No. 4,297,733 have been recorded, can examine whether or not therunning speed during reproduction is coincident with that duringrecording, by using the reproduced output of said pilot signal.

These and other objects of the present invention will become apparentfrom the following detailed description with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a prior art technique.

FIG. 2, consisting of (a)-(c), is a diagram of a first embodiment of theinvention where the tape which was run in the long time mode duringrecording is run in the standard mode during reproduction.

FIGS. 3 and 4, both consisting of (a)-(c), are similar to FIG. 2 exceptthat the tape which has been run in the standard mode during recordingis run in the long time mode during reproduction

FIG. 5(A) is an electrical circuit diagram of a detector for detectingdifference in running speed between recording and reproduction in thefirst embodiment of the invention.

FIG. 5(B) is a graph illustrating variation of the output of thefrequency-to-voltage converter circuit 103 of FIG. 5(A).

FIG. 6 illustrates part of a program of the sequence control circuit ofFIG. 5(A).

FIGS. 7(a) and 7(b) are diagrams of a second embodiment of the inventionwhere the tape which was run in the long time mode during recording isrun in the standard mode during reproduction.

FIGS. 8(a) and 8(b) are similar to FIGS. 7(a) and 7(b) except that thetape which was run in the standard mode during recording is run in thelong time mode during reproduction.

FIG. 9 is an electrical circuit diagram of a detector for detectingdifference in running speed between the recording and reproduction inthe second embodiment of the invention.

FIG. 10 illustrates a program of the switching control circuit of FIG.9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 2, 3 and 4 illustrate the principle of the invention, when thehelical scan type rotating head is used as a head for recording andreproduction.

FIG. 2(a) illustrates recording tracks on a magnetic tape of which a0,a1 . . . have been recorded by a recording head of plus azimuth, and b0,b1, . . . by another head of minus azimuth, and which has been run inthe long time mode. Against this, suppose reproduction is preformed inthe standard mode on the assumption that the running speed of the tapein the long time mode is 1/2 times that in the standard mode, and thewidth of the recording and reproducing head for the long time mode is1/2 times that of the reproducing head for the standard mode.

When reproducing in the standard mode, therefore, the heads trace asshown by dashed lines. A1, A2, . . . are tracing paths of the plusazimuth head, and B1, . . . are those of the minus azimuth head.

Therefore, the reproduced outputs by the two heads as shown in FIG. 2(b)are such that for A1 field, tracks a0 and a1 are reproduced, for B1field, b2 and for A2 field, a2 and a3. In other words, in A1 and A2fields, the crosstalk components of the adjacent two are detected, sothat the reproduction level is lowered as compared with that in B1field.

Then, by comparing the reproduced output with a prescribed thresholdlevel S, comparison output pulses are obtained as shown in FIG. 2(c).These pulses repeat at a rate of one per 2 fields. FIG. 3 is a diagramof another case where recording has been operated in the standard mode,and reproducing is operated in the long time mode. As shown in FIG.3(a), azimuth-recorded tracks b1 - a1 - b2 - a2 and so on are reproducedby azimuth-reproducing heads of the same width as that of the recordingheads as A1 - B1 -A2 - B2 - A3 - B3 and so on. In F1 field, the sameazimuth track a1 is reproduced. In B1 field, track b1 is reproduced. InA2 field, track a1 is reproduced. The reproduced output levels becomethe same as just 1/2 times slow reproduction is preformed. Uponcomparison with a prescribed threshold level S, one pulse for every 4fields is obtained (FIG. 3(c)).

FIG. 4 illustrates another case where similarly to FIG. 3 the magnetictape which has been run in the standard mode during recording is run inthe long time mode during reproduction. However, the width of thereproducing azimuth head is a half of that of the recording head.

When the azimuth recorded tracks are reproduced by the azimuth head, asshown in FIG. 4(b), almost no reproduced outputs are obtained in the B1and B3 fields. Therefore, as shown in FIG. 4(c), similarly to FIG. 3(c),at a rate of once per 4 fields, comparison output pulses are obtained,and also in the picture display, one noise bar in 4 fields is produced.

Of course, when the running speeds in the recording are the same, bothof the comparison output pulse and the noise bar do not take place.

FIG. 5(A) illustrates an embodiment of a detector circuit for detectingdifference in the running speed.

The circuit includes a plus azimuth head H1; a minus azimuth head H2; aswitching circuit SW for switching between the heads H1 and H2; acomparator 102 for comparison with a threshold level; afrequency-to-voltage converter circuit 103; window comparators 104 to107; AND gates AND1 and AND2; and resistors R1 to R5.

The reproduced outputs from heads H1 and H2 are amplified by amplifier100, and reproduction envelope signals are obtained by envelope detector101. The envelope signal is compared with the prescribed threshold valueby comparator 102 to obtain periodic noise bar detection pulses as shownon lines (c) in FIGS. 2, 3 and 4. The detection pulses are converted byconverter circuit 103 to a voltage proportional to the reciprocal of theperiod as shown in FIG. 5(B), and then applied to one of two inputs ofeach of comparators 104 to 107, the other inputs of which are suppliedwith respective reference voltages V1 to V4 from a voltage divider ofresistors R1 to R5 across an electrical power source or battery Vcc.When the output voltage of converter 103 lies between V1 and V2, theoutput of AND1 assumes a high level, and when between V3 and V4, theoutput of AND2 takes on a high level. In other words, when one noise barin every two fields is detected, it is AND gate AND1 that produces anoutput of high level indicating that while recording was in the longtime mode, reproduction is in the standard mode. And when once in everyfour fields, it is AND gate AND2 that produces an output of high level,indicating detection of the fact that while recording was in thestandard mode, reproducing is in the long time mode.

This output is applied to sequence control circuit 108.

FIG. 6 is a diagram illustrating part of a program of the sequencecontrol circuit 108.

At first, the preset mode by the user is read in and whether it is thestandard mode or the long time mode is determined. In the case of thestandard mode, the tape is caused to run in the standard mode to examinewhether or not the output of AND1 is high level. Upon detection of lowlevel of AND1, the reproduced video signals are given to a TV monitorwithout further alternation. Upon detection of high level, the long timemode is used. Also in case where the preset mode is the long time one,the tape is caused to run at a speed corresponding to the long timemode, and whether or not the output of AND2 is high level is examined.Upon detection of low level of AND2, the reproduced video signals areapplied without further alternation of the TV monitor. Upon detection ofhigh level, the tape is caused to run in the standard time mode. By thisthe same mode as recording was operated is rendered operative duringreproduction, thereupon a noise-bar-free picture is obtained on the TVmonitor.

It is to be noted that trhough the foregoing embodiment has beendescribed in connection with the ratio of the running speed of the tapeduring recording to that during reproduction taken at 2:1 or 1:2, forother values of the running speed ratio, it is of course possible toachieve such detection.

It is also noted that though the period of the noise bar detected pulsesis sensed by using a frequency-to-voltage converter, it is of coursepossible to use a timer circuit or other suitable means for detectingpurposes.

Also though the foregoing embodiment has been described taking as thereproducing apparatus an example of an apparatus for reproducing amagnetic tape which was azimuth-recorded, the invention is applicable toanother or optical type reproducing apparatus provided that a differencebetween the recording and reproducing speeds results in aberration fromthe recording tracks. For, if so, the reproduced output level variesperiodically, detection of its period enables adjustment of thereproducing speed.

Next described is a second embodiment of the invention.

FIGS. 7 and 8 are principle diagrams for explaining the secondembodiment.

FIG. 7(a) illustrates recording tracks on a magnetic tape, where a1, a2,. . . are those of the tracks which have been recorded by the plusazimuth recording head, and b1, b2, . . . are the others which have beenrecorded by the minus azimuth recording head, and these tracks alternateas a1 - b1 - a2 - b2 - a3 - b3 and so on in the long time mode.

It is to be noted here that for each of tracks a1, a3, a5, . . . a pilotsignal of frequency f1 has been recorded in superimposing relation onthe video signals, for each of tracks b1, b3, b5, . . . another pilotsignal of frequency f2, for each of tracks a2, a4, a6, . . . anotherpilot signal of frequency f4, and for each of tracks b2, b4, b6, . . .another signal of frequency f3. The frequencies f1, f2, f3 and f4 haverelationships: f1<f2<f3<f4, f2-f1=f4-f3=f5; f4-f2=f3-f1=f6; and f5≠f6.When the f1, f2, f3 and f4 pilot signal-recorded tracks are individuallyreproduced, those of the pilot signals which have been recorded in theadjacent tracks are reproduced as crosstalk components. By multiplyingthe reproduced output by the one of signals F1, F2, F3 and F4 which havethe same frequency as the pilot signal in the track being reproducedhas, the crosstalk components are extracted as signals of thefrequencies f5 and f6. Then, the levels of the signals f5 and f6 arecompared with each other to obtain a tracking control signal(hereinafter referred to as "ATF" signal). The foregoing description ismade as an example of the method for obtaining the "ATF" signal. In thisconnection it should be pointed out that the frequencies of the signalsto be superimposed on the video signals may be combined in anotherdifferent way, and many other combinations can be considered.

Now suppose that such recorded tracks are reproduced at a faster runningspeed (standard mode) that the recording speed (long time mode). In FIG.7(a), the head tracing paths during reproduction in the standard modeare shown by dashed lines with an arrow α indicating the direction inwhich the tape is run and another arrow β indicating the direction inwhich the head scans. Also the running speed of the tape in the longtime mode is assumed to be a half of that in the standard mode, and thewidth of the reproducing head for the standard mode is assumed to be 2times that of the recording head for the long time mode. With such anarrangement, when tracing at the tape speed for the standard mode, thetrack pattern on the tape does not match the inclination of the path ofthe reproducing head, and moreover no correspondence between thereproduced output of the pilot signal (f1-f4) recorded in the track tobe reproduced and the frequency signal (F1-F4) to be mixed with thereproduced output can be taken. For this reason, as shown on line (b) inFIG. 7, the "ATF" signal varies by a period of 2 frames. Referring toFIG. 7(a), if the reproducing head scan B2 field, because the frequencysignal to be multiplied during scanning of the B2 field is F3, the "ATF"signal would control the phase of rotation of the capstan so that amongthe tracks on which the pilot signal of the same frequency as that ofthe signal F3, the nearest track b4 to the B2 is to be reproduced.However, because the direction of movement of the reproducing head isdifferent from the direction of path of the track by the aforesaidreason, a good tracking condition is attained during a B2 field only atan intermediate point in the B2 field. And at the start point ofscanning the B2 field, the pilot signal f4 in the preceding adjacenttrack a4 is largely reproduced, and at the terminal point of scanning,the pilot signal f1 in the following adjacent track a5 is largelyreproduce. As a result, the ATF output takes on a high level at thestart point in order to speed up the tape movement, and low level at theterminal point in order to slow down the tape movement.

Now assuming that, as usual, the voltage of the ATF output is Vcc/2 whenthe good tracking condition is attained, then the ATF output representsa vibrating waveform of 2-frame period with Vcc/2 at the center.

FIG. 8 illustrates a mistracking condition resulting from the use of thelong time mode during reproduction despite recording has been operatedin the standard mode. What is different from FIG. 7 is that themistracking condition repeats itself in a period of just 4 frames.Therefore, the ATF output vibrates by the 4-frame period as shown online (b) in FIG. 8. In conclusion, when reproduction is performed at aspeed of tape movement different from that at which the tape was runduring recording, the ATF output signal varies its magnitudeperiodically.

FIG. 9 is a block diagram of a fundamental circuit of putting theabove-described principles into practice. The circuit includesreproducing heads 28a and 28b; a demodulator circuit 29 of knownconstruction for obtaining the ATF signal from the pilot signals (f1-f4)for tracking reproduced by the reproducing head 28a, 28b (detailed, forexample, in the specification of U.S. Pat. No. 4,297,733); a rotationcontrol servo circuit 30 for capstan motor 14; band pass filters 15 and16 for extracting only 2-frame and 4-frame periodic signalsrespectively; rectifier and detector circuits 17 and 18 for the filters;comparators 19 and 20 cooperating with a constant voltage source 25 ofadjustable output voltage E1; integrator circuits 21 and 22; comparators23 and 24 cooperating with a constant voltage source of adjustablevoltage E2; and switching control circuit 27 for changing the taperunning speed.

The ATF signal from the ATF demodulator circuit 29 is directed not onlyto the capstan servo circuit but also to the band pass filters BPFs 15and 16 where only the signals of 2-frame period and 4-frame period (inthe case of the NTSC signal reproducing VTR, 15 Hz and 7.5 Hzrespectively) are allowed to pass therethrough to detectors 17 and 18.The outputs of detectors 17 and 18 in the form of direct currentsignals, because of their including simple noise components, arecompared with the threshold voltage E1 by comparators 19 and 20. Onlywhen above E1 level, the outputs of comparators 19 and 20 are averagedby integrator circuits 21 and 22. Then only when the outputs ofintegrators 21 and 22 exceed above the threshold voltage E2, comparators23 and 24 produce outputs A and B of high level respectively that theoutput A is of H level shows that the tape which was run at the longtime mode during recording is reproduced at the standard speed. That theoutput B is of H level, indicates that the tape which was run at thestandard speed during recording is reproduced in the long time mode. Ofcourse, when what has been recorded in the standard mode is reproducedin the same mode, or when what has been recorded in the long time modeis reproduced in the long time mode, both of the outputs A and B do notbecome H level, as a matter of course. The outputs A and B are appliedto the switching control circuit 27 controlling the running speed of thetape in accordance with the outputs A and B.

FIG. 10 illustrates part of a program of switching control circuit 27.

At first, the preset mode by the user is read in, and whether it is thestandard mode or the long time mode is discriminated. In the case of thestandard mode, the tape is caused to run at the normal speed. Thenwhether or not the output A is of high level is examined. Upon detectionof the output A of low level, the reproduced video signals are emergedto a TV monitor without further alternation. Upon detection of highlevel, the speed of the tape movement is changed to the slow one. In thecase of the long time mode presetting, the tape is caused to run at theslow speed corresponding to the long time mode, while whether or not theoutput B is of high level is examined. Upon detection of the output B oflow level, the reproduced video signals are applied without furtheralternation onto the TV monitor. Upon detection of high level, the speedof tape movement is changed to the standard one. Thus only after thesame mode is set up during reproduction as was set during recording,noise bar free, near pictures are obtained on the TV monitor.

It is to be noted that though the foregoing embodiment has beendescribed in connection with the ratio of the tape speed in the standardmode to that in the long time mode taken at 2:1, generally speaking bythe ratio of N:1 (where N is an integer), it is when the tape is run atN times faster a speed than the required one during reproduction thatthe ATF output signal varies by a period of 2/(n-1), and it is when at1/N times faster a speed, that the period is 2N-frames. Therefore, asBPFs 15 and 16, those having transmittance in frequencies of 15Hz and15/N Hz respectively must be selected for use. So long as thisrequirement is fulfilled, the present invention is applicable to anytype reproducing apparatus where the speed ratio is other than 2:1, orthree or more different reproduction speeds are provided. In thisembodiment the technique of detecting the periodic variation of the ATFoutput signal uses BPFs and detector circuits. However, is also possiblethat the ATF output is passed through an LPF to reduce noise, thenpulses are formed at points when the ATF output goes across Vcc/2, thenthe time interval between the successive two pulses is converted to avoltage by the frequency-to-voltage converter, and then the outputs Aand B are obtained by the window comparators.

Also though, in this embodiment, the ATF signal itself is utilized, thedifference between the recording and reproducing speeds can be otherwisedetected by sensing the level of the frequency signal such as f2-f1, orf4-f2 in the front stage. It is also possible to detect the differencebetween the recording and reproducing speeds by the reproduced period ofone pilot signal out of the frequencies f1, f2, f4 and f3.

Also though the foregoing embodiment has been described in connectionwith the use of four pilot signals of different frequencies (f1-f4)during recording, the present invention is applicable to all other typereproducing apparatus, provided that from the tape on which pilotsignals of different frequencies have been recorded in adjacent tracksare reproduced the pilot signals to obtain the tracking signal.

As has been described in greater detail above, even with a recordingmedium having no CTL signals recorded theron, the invention makes itpossible to detect coincidence or difference between the recording speed(the running speed of the recording medium during recording) and thereproducing speed (the running speed of the recording medium duringreproduction). This is done by the reproduced output of reproducingmeans for reproducing information signals.

Also by using its detected output, it is possible to automatically bringthe reproducing speed into coincidence with the recording speed.

it is to be understood that the present invention is not limited to theabove-described embodiments, and that many applications and variationsare possible within the spirit and scope of the invention construed inthe appended claims.

What we claim:
 1. A reproducing apparatus comprising:(a) transportingmeans for selectively transporting a tape-shaped recording medium at oneof at least two different running speeds for reproducing purposes; (b)reproducing means for reproducing information recorded on saidtape-shaped recording medium as it is transported by said transportingmeans; and (c) discriminating means for determining whether or not thetransportation speed of said transporting means is coincident with therecording speed of the information recorded on said tape-shapedrecording medium, said discriminating means including envelope detectormeans for detecting an envelope of the reproduced output of saidreproducing means.
 2. A reproducing apparatus according to claim 1,wherein said discriminating means further includes converting means forconverting the period of variation of the output of said envelopedetector means to a voltage.
 3. A reproducing apparatus comprising:(a)transporting means for selectively transporting a tape-shaped recordingmedium at one of at least two different running speeds for reproducingpurposes; (b) reproducing means for reproducing information recorded onsaid tape-shaped recording medium as it is transported by saidtransporting means; (c) discriminating means for determining whether ornot the transportation speed of said transporting means is coincidentwith the recording speed of the information recorded on said tape-shapedrecording medium; (d) the information having pilot signals recorded insuperimposing relation; and (e) said detection means being arranged todetect whether or not said running speed and said recording speed arecoincident with each other by using said reproduced pilot signals.
 4. Areproducing apparatus for reproducing information signals from atape-shaped recording medium on which a plurality of pilot signals ofdifferent frequencies for tracking control and information signals arerecorded in superimposing relation, comprising:(a) transporting meansfor selectively transporting said tape-shaped recording medium at one ofat least two different running speeds for the purpose of reproducingsaid information signals; (b) reproducing means for reproducing saidinformation signals and said pilot signals recorded on said tape-shapedrecording medium as it is transported by said transporting means; and(c) discriminating means for determining whether or not thetransportation speed of said transporting means is coincident with therecording speed of said information signals by the reproduced output ofsaid pilot signals.
 5. A reproducing apparatus according to claim 4,further comprising:transportation control means responsive to thedetected output of said discriminating means for changing the runningspeed of said transporting means.
 6. A reproducing apparatus accordingto claim 4, wherein said reproducing means includes a reproducing headobliquely scanning said recording medium.
 7. A reproducing apparatusaccording to claim 6, wherein said reproducing head includes a firstreproducing head having a plus azimuth angle, and a second reproducinghead having a minus azimuth angle.
 8. A reproducing apparatus accordingto claim 4, wherein said information signals are video signals.
 9. Areproducing apparatus according to claim 4, further comprising:trackingcontrol means for obtaining a tracking control signal from thereproduced output of said pilot signals.
 10. A reproducing apparatusaccording to claim 9, wherein said discriminating means detects theperiod of variation of the level of said tracking control signal.
 11. Areproducing apparatus for reproducing information signals from atape-shaped recording medium on which a plurality of pilot signals ofdifferent frequencies for tracking control and information signals arerecorded in superimposing relation, comprising:(a) transporting meansfor selectively transporting said tape-shaped recording medium at one ofat least two different running speeds for the purpose of reproducingsaid information signals; (b) reproducing means for reproducing saidinformation signals and said pilot signals recorded on said tape-shapedrecording medium as it is transported by said transporting means; (c)tracking control means for obtaining a tracking control signal from thereproduced output of said pilot signals; and (d) discriminating meansfor determining whether or not the transportation speed of saidtransporting means is coincident with the recording speed of saidinformation signals based on said tracking control signal.
 12. Areproducing apparatus according to claim 11, wherein said discriminatingmeans includes detection means for detecting the period of variation ofthe level of said tracking control signals.
 13. A reproducing apparatusaccording to claim 12, wherein said detecting means includes aseparation circuit for separating a component having a predeterminedfrequency from said tracking control signals.
 14. A reproducingapparatus according to claim 13, wherein said detection means furtherincludes a comparison circuit for comparing an output level of saidseparation circuit with a predetermined level.
 15. A reproducingapparatus according to claim 11, further comprising transportationcontrol means responsive to the output of said discriminating means forchanging the running speed of said transporting means.
 16. A reproducingapparatus for reproducing information signals from a tape-shapedrecording medium on which a plurality of pilot signals of differentfrequencies for tracking control and information signals are recorded insuperimposing relation, comprising:(a) transporting means forselectively transporting said tape-shaped recording medium at one of atleast two different running speeds for the purpose of reproducing saidinformation signals; (b) reproducing means for reproducing saidinformation signals and said pilot signals recorded on said tape-shapedrecording medium as it is transported by said transporting means; (c)tracking control means for obtaining a tracking control signal from thereproduced output of said pilot signals; (d) separation means forseparating a component having a predetermined frequency from saidtracking control signal; and (e) discriminating means for determiningwhether or not the transportation speed of said transporting means iscoincident with the recording speed of said information signals based onthe output of said separation means.
 17. A reproducing apparatus forreproducing information signals from a tape-shaped recording medium onwhich a plurality of pilot signals of different frequencies for trackingcontrol and information signals are recorded in superimposing relation,comprising:(a) transporting means for selectively transporting saidtape-shaped recording medium at one of at least two different runningspeeds for the purpose of reproducing said information signals; (b)reproducing means for reproducing said information signals and saidpilot signals recorded on said tape-shaped recording medium as it istransported by said transporting means; (c) tracking control means forobtaining a tracking control signal from the reproduced output of saidpilot signals; (d) first comparison means for comparing a level of afirst signal related to the reproduced output of said pilot signals witha predetermined level; (e) second comparison means for comparing a levelof a second signal related to the reproduced output of said pilotsignals with a predetermined level; and (f) discriminating means fordetermining whether or not the transportation speed of said transportingmeans is coincident with the recording speed of said information signalsbased on both of the output of said first comparison means and theoutput of said second comparison means.
 18. A reproducing apparatus forreproducing information signals from a tape-shaped recording medium,comprising:(a) transporting means for selectively transporting saidtape-shaped recording medium at one of at least two different runningspeeds for the purpose of reproducing said information signals; (b)reproducing means for reproducing said information signals recorded tosaid tape-shaped recording medium as it is transported by saidtransporting means, said reproducing means having at least one rotatinghead; (c) first comparison means for comparing a level of a signalformed from output signals of the rotating head with a firstpredetermined level; (d) second comparison means for comparing the levelof the signal when a second predetermined level; and (e) discriminatingmeans for determining whether or not the transportation speed of saidtransporting means is coincident with the recording speed of saidinformation signals based on both of the output of said first comparisonmeans and the output of said second comparison means.